Shaped cutter surface

Abstract

A cutter for a drill bit used in a geological formation includes a shaped ultra hard working surface. The cutter with the shaped working surface is mounted on a drill bit to provide desired cutting characteristics. The shaped working surface provides varied cutting characteristics depending upon the shape, and the characteristics can vary depending upon the depth of the cut.

1. A cutter for an earth boring drag bit, the cutter comprising:
 an ultrahard material layer bonded to a substrate, the ultrahard material layer comprising a peripheral side surface and a shaped working surface, said working surface intersecting said peripheral side surface, wherein a peripheral edge is defined by said intersection, said peripheral edge forming at least a cutting edge, wherein the shaped working surface comprises an axially asymmetrical curved surface, the axially asymmetrical curved surface comprising a smoothly continuous compound curve, wherein the smoothly continuous compound curve comprises a continuously curving convex portion and concave portions extending from opposite sides of said convex portion, wherein any first point on the peripheral edge intersected by an axial plane extending across the convex portion and the concave portions and through a central axis of said ultrahard material layer is at a level as measured axially from a second point on the convex portion that is at a distance from said first point no less than all levels of the concave portions along said plane as measured axially from said second point. 
 
   
   
     2. The cutter of  claim 1 , wherein the shaped working surface comprises a high point and a low point in an axial direction and wherein an imaginary cross-section, taken through the shaped working surface perpendicular to the axial direction and halfway between the high point and the low point, has an area that is greater than about 20% of the total area of the shaped working surface. 
   
   
     3. The cutter of  claim 1 , wherein the shaped working surface comprises a high point and a low point in an axial direction and wherein an imaginary cross-section, taken through the shaped working surface perpendicular to the axial direction and halfway between the high point and the low point, has a perimeter length that is greater than about 20% of a perimeter of the shaped working surface. 
   
   
     4. The cutter of  claim 1 , wherein the shaped working surface comprises a high point and a low point in an axial direction and wherein an imaginary cross-section, taken through the shaped working surface perpendicular to the axial direction and halfway between the high point and the low point, has an area that is greater than about 50% of a total area of the shaped working surface. 
   
   
     5. The cutter of  claim 1 , wherein the shaped working surface comprises a high point and a low point in an axial direction and wherein an imaginary cross-section, taken through the shaped working surface perpendicular to the axial direction and halfway between the high point and the low point, has a perimeter length that is greater than about 50% of a perimeter of the shaped working surface. 
   
   
     6. The cutter of  claim 1 , wherein the shaped working surface comprises a relative high point inward from the peripheral edge of the ultrahard material layer, the relative high point defined by a convex curved surface portion that is connected to the peripheral edge of the ultrahard material layer with a concave curved surface. 
   
   
     7. The cutter of  claim 1  wherein the edge is defined by the intersection of a linearly extending surface of the ultrahard material layer and the working surface. 
   
   
     8. The cutter of  claim 1  wherein the peripheral edge is axially asymmetrical. 
   
   
     9. The cutter of  claim 1  wherein said at least a cutting edge includes a portion of said peripheral edge that is higher than a majority of the remainder of the peripheral edge as measured from the substrate. 
   
   
     10. The cutter of  claim 1  wherein the convex portion is elongated in plan view and is diametrically symmetrical about a diameter of said cutter spanning a longest span of said convex portion. 
   
   
     11. A cutter for an earth boring drag bit, the cutter comprising:
 an ultrahard material layer bonded to a substrate, the ultrahard material layer comprising a peripheral side surface and a shaped working surface, said working surface intersecting said peripheral side surface, wherein a peripheral edge is defined by said intersection surrounding said working surface, said peripheral edge forming at least a cutting edge, wherein the shaped working surface comprises a high point and a low point in an axial direction and wherein an imaginary cross-section, taken through the shaped working surface perpendicular to the axial direction and halfway between the high point and the low point, has an area that is greater than about 20% of a total area of the shaped working surface wherein the working surface comprises an axially asymmetrical curved surface comprising a continuously curving convex portion and concave portions extending from opposite sides of said convex portion, wherein any first point on the peripheral edge intersected by an axial plane extending across the convex portion and the concave portions and through a central axis of said ultrahard material layer is at a level as measured axially from a second point on the convex portion that is at a distance from said first point no less than all levels of the concave portions along said plane as measured axially from said upper point. 
 
   
   
     12. The cutter of  claim 11  wherein the edge is defined by the intersection of a linearly extending surface of the ultrahard material layer and the working surface. 
   
   
     13. The cutter of  claim 11  wherein the peripheral edge is axially asymmetrical. 
   
   
     14. The cutter of  claim 11  wherein said at least a cutting edge includes a portion of said peripheral edge that is higher than a majority of the remainder of the peripheral edge as measured from the substrate. 
   
   
     15. The cutter of  claim 11  wherein the convex portion is elongated in plan view and is diametrically symmetrical about a diameter of said cutter spanning a longest span of said convex portion. 
   
   
     16. A cutter for an earth boring drag bit, the cutter comprising:
 an ultrahard material layer bonded to a substrate, the ultrahard material layer comprising a peripheral side surface and a shaped working surface, said working surface intersecting said peripheral side surface, wherein a peripheral edge is defined by said intersection surrounding said working surface, said peripheral edge forming at least a cutting edge, wherein the shaped working surface comprises a high point and a low point in an axial direction and wherein an imaginary cross-section, taken through the shaped working surface perpendicular to the axial direction and halfway between the high point and the low point, has a perimeter length that is greater than about 20% of the perimeter of the shaped working surface wherein the working surface comprises an axially asymmetrical curved surface comprising a continuously curving convex portion and concave portions extending from opposite sides of said convex portion, wherein any first point on the peripheral edge intersected by an axial plane extending across the convex portion and the concave portions and through a central axis of said ultrahard material layer is at a level as measured axially from a second point on the convex portion that is at a distance from said first point no less than all levels of the concave portions along said plane as measured axially from said second point. 
 
   
   
     17. The cutter of  claim 16  wherein the edge is defined by the intersection of a linearly extending surface of the ultrahard material layer and the working surface. 
   
   
     18. The cutter of  claim 16  wherein the peripheral edge is axially asymmetrical. 
   
   
     19. The cutter of  claim 16  wherein said at least a cutting edge includes a portion of said peripheral edge that is higher than a majority of the remainder of the peripheral edge as measured from the substrate. 
   
   
     20. The cutter of  claim 16  wherein the convex portion is elongated in plan view and is diametrically symmetrical about a diameter of said cutter spanning a longest span of said convex portion. 
   
   
     21. An earth boring drag type drill bit comprising:
 a bit body; and
 at least one cutter held by the bit body, the at least one cutter comprising an ultrahard material layer having a peripheral side surface and a shaped working surface, said working surface intersecting said peripheral side surface, wherein a peripheral edge is defined by said intersection surrounding said working surface, said peripheral edge forming at least a cutting edge, the shaped working surface including an axially asymmetrical curved surface comprising a continuously curving convex portion continuously curving convex portion and concave portions extending from opposite sides of said convex portion, wherein any first point on the peripheral edge intersected by an axial plane extending across the convex portion and the concave portions and through a central axis of said ultrahard material layer is at a level as measured axially from a second point on the convex portion that is at a distance from said first point no less than all levels of the concave portions along said plane as measured axially from said second point. 
 
 
   
   
     22. The drill bit of  claim 21  further comprising a plurality of cutters having ultrahard working surfaces selectively positioned on the bit body, wherein the shaped surface and the positions of the plurality of cutters produces a balance of forces on the drill bit during operation. 
   
   
     23. The drill bit of  claim 21  further comprising a plurality of cutters having ultrahard working surfaces selectively positioned on the bit body, wherein the shaped surface and the positions of the plurality of cutters produces a net unbalanced force on the drill bit during operation. 
   
   
     24. The drill bit of  claim 21  further comprising a plurality of cutters having ultrahard working surfaces selectively positioned on the bit body, wherein the shaped surface and the positions of the plurality of cutters produces a net unbalanced force on the drill bit during operation to facilitate directional drilling. 
   
   
     25. The drill bit of  claim 21  wherein the edge is defined by the intersection of a linearly extending surface of the ultrahard material layer and the working surface of said at least one cutter. 
   
   
     26. The bit of  claim 21  wherein the peripheral edge is axially asymmetrical. 
   
   
     27. The bit of  claim 21  wherein said at least a cutting edge includes a portion of said peripheral edge that is higher than a majority of the remainder of the peripheral edge as measured from the substrate. 
   
   
     28. The earth boring drag bit of  claim 21  wherein the convex portion is elongated in plan view and is diametrically symmetrical about a diameter of said cutter spanning a longest span of said convex portion. 
   
   
     29. An earth boring drag type drill bit comprising:
 a bit body; and 
 at least one cutter held by the bit body, the at least one cutter having comprising an ultrahard material layer bonded to a substrate, the ultrahard material layer comprising a peripheral side surface and a shaped working surface, said working surface intersecting said peripheral side surface, wherein a peripheral edge is defined by said intersection surrounding said working surface, said peripheral edge forming at least a cutting edge, the shaped working surface including a high point and a low point in an axial direction of the cutter and wherein an imaginary cross-section, taken through the shaped working surface perpendicular to the axial direction of the cutter and halfway between the high point and the low point, has an area that is greater than about 20% of a total area of the shaped working surface wherein the working surface comprises an axially asymmetrical curved surface comprising a continuously curving convex portion and concave portions extending from opposite sides of said convex portion, wherein any first point on the peripheral edge intersected by an axial plane extending across the convex portion and the concave portions and through a central axis of said ultrahard material layer is at a level as measured axially from a second point on the convex portion that is at a distance from said first point no less than all levels of the concave portions along said plane as measured axially from said second point. 
 
   
   
     30. The drill bit of  claim 29  wherein the edge is defined by the intersection of a linearly extending surface of the ultrahard material layer and the working surface of said at least one cutter. 
   
   
     31. The bit of  claim 29  wherein the peripheral edge is axially asymmetrical. 
   
   
     32. The bit of  claim 29  wherein said at least a cutting edge includes a portion of said peripheral edge that is higher than a majority of the remainder of the peripheral edge as measured from the substrate. 
   
   
     33. The earth boring drag bit of  claim 29  wherein the convex portion is elongated in plan view and is diametrically symmetrical about a diameter of said cutter spanning a longest span of said convex portion. 
   
   
     34. An earth boring drag type drill bit comprising:
 a bit body; and 
 at least one cutter held by the bit body, the at least one cutter having comprising an ultrahard material layer bonded to a substrate, the ultrahard material layer comprising a peripheral side surface and a shaped working surface, said working surface intersecting said peripheral side surface, wherein a peripheral edge is defined by said intersection surrounding said working surface, said peripheral edge forming at least a cutting edge, the shaped working surface including a high point and a low point in an axial direction of the cutter and wherein an imaginary cross-section, taken through the shaped working surface perpendicular to the axial direction of the cutter and halfway between the high point and the low point, has a perimeter length that is greater than about 20% of a total perimeter length of the shaped working surface wherein the working surface comprises an axially asymmetrical curved surface comprising a continuously curving convex portion and concave portions extending from opposite sides of said convex portion, wherein any first point on the peripheral edge intersected by an axial plane extending across the convex portion and the concave portions and through a central axis of said ultrahard material layer is at a level as measured axially from a second point on the convex portion that is at a distance from said first point no less than all levels of the concave portions along said plane as measured axially from said second point. 
 
   
   
     35. The drill bit of  claim 34  wherein the edge is defined by the intersection of a linearly extending surface of the ultrahard material layer and the working surface of said at least one cutter. 
   
   
     36. The bit of  claim 34  wherein the peripheral edge is axially asymmetrical. 
   
   
     37. The bit of  claim 34  wherein said at least a cutting edge includes a portion of said peripheral edge that is higher than a majority of the remainder of the peripheral edge as measured from the substrate. 
   
   
     38. The earth boring drag bit of  claim 34  wherein the convex portion is elongated in plan view and is diametrically symmetrical about a diameter of said cutter spanning a longest span of said convex portion. 
   
   
     39. An earth boring drag type drill bit comprising:
 a bit body; and 
 at least one cutter held by the bit body, the at least one cutter having an ultrahard working surface, the working surface including a varied curvature along a critical area of the working surface providing a varied effective back rake angle along a selected critical area of the cutter face, the varied curvature comprising a convex curve portion that connects on one side with a concave curve portion which extends to a side edge and connects on another side with another concave curve portion that extends to another side edge to provide a working surface configured to plow through formation and direct cuttings sideways away from the convex curve portion of the working surface, wherein the curvature of the working surface is varied based upon the intended position of the cutter on the drill bit, and to relatively increase the effective back rake angle in one critical area of the cutter face predicted to have a relatively large depth of cut at the interface with the formation and the curvature is varied to relatively reduce the effective back rake angle of a chamfer in another critical area of the cutter face predicted to have a relatively small depth of cut.